1. Field of the Invention
This invention relates to an ink-jet recording method, an ink-jet recording apparatus using such method, an information-processing apparatus using such apparatus as an output device for obtaining a high-quality image on a recording medium, and a recorded product produced by the above apparatuses. Especially, the ink-jet recording method has the step of ejecting an aqueous liquid for making a color material insoluble or in an aggregated form. The term "recording" includes the meaning of printing, image-forming, dyeing, and all kinds of a supply of ink or the like on a recording medium such as cloth, textile, paper, OHP sheet, and so on. Therefore, the present invention can be adaptable not only to a specific field (i.g., information processing ) but also to a wide range of the technical fields that use the recording medium.
2. Description of the Related Art
Among conventional recording apparatuses, an ink-jet type recording apparatus adapted to execute recording on a recording medium (sheet of recording paper, cloth, sheet of plastic material or the like) by ejecting ink from a plurality of ejecting ports disposed on the recording elements while generating few noisy sound without any impact induced by each recording operation makes it possible to perform each recording operation not only at a high density but also at a high speed. For this reason, a number of ink-jet type recording apparatuses are utilized for an information processing apparatus on the commercial basis.
In practice, the ink-jet recording apparatus is used as a printer located at an output terminal of an information processing apparatus, e.g., a copying machine, a facsimile, a computer, a word processor, a work station or the like or as a handy or portable printer to be equipped in operative association with a personal computer, a host computer, an optical disc unit, a video unit or the like.
A conventional recording apparatus as mentioned above includes a carriage for mounting a recording means (recording head) and ink-supplying means (ink tank) thereon , a conveying means for conveying a recording medium, a driving means for reciprocally displacing a recording head in the direction at a right angle relative to the direction of conveyance of a recording medium, and a controlling means for controlling the ejection of ink from the recording head, the conveyance of a recording medium and the reciprocal displacement of the recording head with the aid of driving means.
The recording head adapted to eject ink droplets from a plurality of ejection ports thereof is serially scanned in the direction at a right angle relative to the direction of conveyance of the recording medium (i.e., in the main scanning direction), and subsequently, the recording medium is intermittently conveyed at a quantity of displacement thereof equal to the recorded width of the recording medium while no recording operation is performed. With this recording method, recording is executed in response to a recording signal by ejecting ink onto the recording medium. For this reason, the foregoing recording method is widely used as a quiet recording apparatus capable of being practiced at an inexpensive running cost. When a large number of nozzles each adapted to eject ink therefrom is formed on the recording head along a straight line extending at a right angle relative to the direction of displacement of the recording head relative to the recording medium, recording can be executed by a quantity of width corresponding to the number of nozzles by simultaneously scanning the recording head on the recording medium. This makes it possible to perform a recording operation at a higher speed.
It should be added that a recording apparatus capable of forming a full color image has been put in practical use. The apparatus is able to mount a recording head adapted to eject three or four kinds on inks, i.e., primary colors (yellow (Y), magenta (M), and cyan (C)), or with black (Bk), and ink tanks of these inks.
In the conventional ink-jet recording method and apparatus, however, it is difficult to obtain an image with an extremely high quality enough to request to the user's demand because of the following reasons. That is, the conventional method and apparatus do not prevent (i) a spread of ink on the boundary areas among black (Bk), yellow (Y), magenta (M), and cyan (C); and (ii) a formation of an black image at high-density without causing any feathering, all at once.
For obtaining a multiple-color image on a sheet of general paper, in general, a quick-drying ink that soaks into the general paper at high speed has been used. Thus it is able to prevent a spread of the ink on the boundary area between the colors that constitute the image.
In the case of using the quick-drying ink, however, a black-image portion tends to become of a low concentration while color image portions except the black tend to become of a low coloring.
Furthermore, in the case of recording a line drawing such as characters, the ink tends to spread along fibers of paper (i.e., so-called feathering). Especially, the feathering generated in the character recorded by the black ink is easily to come into prominence without a sharpness. As a result, the image having an extremely low qualities on the whole can be obtained.
By using the ink of comparatively low rate of permeating into the general paper, in general, the number of the ink droplets to be placed at one point should be increased to some degree for obtaining a high-quality image without causing a conspicuous feathering. In this case, however, the quality of a recording image can be remarkably damaged.
For eliminating these shortcomings, a recording apparatus having a heating means that accelerates ink-drying has been practically used for obtaining a multiple-color image that comes out well without any spread of ink between the colors. However, this kind of the way to solve the problems require a large-sized apparatus and its costly manufacturing process.
In this way, therefore, the problems to be solved are: providing a high-quality image that comprises black-color portion with a high image density; and preventing any feathering and spread of the ink between the inks such as of black and other colors, which are directly-opposed ideas.
To solve the problems, a document of Japanese Patent Application Laying-Open No. 146355/1991 offers a recording method includes the step of recording an image except a predetermined area along a boundary line between a black image portion and another color image portion. In this method, therefore, the data to be used for recording the image is changed.
In a document of Japanese Patent Application Laying-Open No. 158049/1992, a recording method includes the step of switching two recording heads. That is one is for recording a plurality of colors and the other is for recording characters in accordance with the image to be recorded. In this case, however, these heads form black image portions in different ways, respectively. When the black image portions formed by different heads are mixed with or adjacent to each other, there is the state or quality of being incompatible.
Furthermore, it may be possible to prevent a spread of ink on a boundary between a black image portion and another color image portion by forming a black area along the boundary by placing color inks one upon another. In principle, that is, a black color can be expressed by placing three principle colors (Y, M, and C) on top of one another (i.e., color-blending). In this case, however, a coloring of the black thus formed is worse than that of the pure black.
Moreover, Japanese Patent Application Laying-Open No. 84992/1981 and Japanese Patent Application Laying-Open No. 63185/1989 disclose the techniques of using an aqueous liquid that makes a dyestuff of ink insoluble.
In Japanese Patent Application Laying-Open No. 84992/1981, a large number of sheets of recording paper is mass-manufactured and then a surface of each sheet thereof is covered with a material that fixes a dyestuff thereon, prior to record an image. In this case, however, a specific type of the recording paper must be used and also a storage device must be required for preserving a large number of sheets of the recording paper mass-manufactured. In addition, therefore, additional devices must be equipped in the recording apparatus or provided as its peripheral devices, resulting in a costly large-sized apparatus. It is noted that, furthermore, there is difficulty to apply the above material on the recording medium so as to form a layer thereof with a predetermined thickness.
Another document, Japanese Patent Application Laying-Open No. 63185/1989 discloses a recording method including the step of placing a clear aqueous liquid (clear ink) that makes a dyestuff insoluble on a recording medium by ejecting the clear ink from an ink-jet recording head. According to that process, a diameter of each dot to be formed by the clear ink is larger than that of ink used for image formation, so that a desired image quality can be attained regardless of slightly slipping out of predetermined positions. In the above process, furthermore, an amount of the clear ink to be placed is larger than that of the color ink to be placed, so that the time required for drying the ink becomes longer and a resulting image can be extremely indistinct.
As described above, each of the conventional methods disclosed in the above documents disclosed in the above documents have some disadvantages. However, means for making a dyestuff of ink insoluble has a possibility of preventing a spread of ink on a boundary between different colors.